This application proposes the creation of a Data Coordinating Center for a multicenter clinical trial entitled "Growth Failure in Children with Renal Diseases". The clinical trial will evaluate, in a double-blind design, linear growth of children with chronic renal failure under treatment with either 1,25-dihydroxyvitamin-D3 or dihydrotachysterol and will assess efficacy and safety of these two treatments. A sample of 120-160 children aged 2-11 years will be followed up to 45 months. Specific objectives of the Data Coordinating Center include: 1) working closely with the Principal Investigator of the clinical trial in the administration and control of the study; 2) ensuring accuracy, reliability, validity, completeness and security of all data; 3) providing expert statistical analysis and interpretation of results. The Data Coordinating Center will be responsible for all document and data forms preparation, study personnel training and orientation, study design and double-binding protocol, data management and quality control as well as interim and final statistical analysis and dissemination of results. The Principal Investigator of this project is Walter H. Carter, Jr., Ph.D., Professor of Biostatistics, Department of Biostatistics, Medical College of Virginia, Richmond, Virginia. The proposed Data Coordinating Center will work in concert with a four-member Executive Committee (including the Principal Investigator and Co-Investigators of the clinical trial) and an Advisory Committee composed of pediatric nephrologists, a biostatistician and a clinical nutritionist. This project has the endorsement of the Chairman of the Department of Biostatistics and the Dean of the School of Basic Sciences, Medical College of Virginia.